`FileReaderSync` is not exposed for ServiceWorker. * https://w3c.github.io/FileAPI/#FileReaderSync * https://github.com/w3c/FileAPI/issues/16
Created attachment 401746 [details] Patch
Thank you, Darin.
Committed r263009: <https://trac.webkit.org/changeset/263009> All reviewed patches have been landed. Closing bug and clearing flags on attachment 401746 [details].
<rdar://problem/64337427>
<rdar://problem/64337428>